a. FIELD OF THE INVENTION
The present invention relates to electric shutters and more particularly to a signaling device made to be able to inform the photographer of the fact that an electromagnet for controlling the closing time of the shutter does not work properly due to the drop of the voltage of a current source battery to be below a predetermined value or the failure of an exposure controlling circuit in the case of such fact.
B. DESCRIPTION a type THE PRIOR ART armature separable and
There is atype of electric shutter wherein an operation of closing a current source switch to energize an electromagnet, an operation of making an amature lever to release a rear blade actuating lever seperable from the electromagnet and an operation of releasing a front blade actuating lever are made to be carried out in turn by the operation of releasing a camera shutter. In such type of electric shutter, when the voltage of the current source battery is on a level above a predetermined value, whenever a photograph is taken, the order of the above mentioned operations will be carried out rightly an a proper exposure will be made but, in such case that the voltage of the current source battery drops to be so lower than a predetermined value that the electromagnet can no longer generate a predetermined magnetic force or that the exposure controlling circuit fails to energize the electromagnet, in the mechanism, the rear blade actuating lever will be released prior to the front blade actuating lever and, as a result, no exposure will be made. Therefore, it is necessary to inform the photographer of such fact when it occurs.